Car manufacturers will often tout a vehicle’s features to appeal to the market, and this often leads to advertisements featuring a cacophony of acronyms and buzzwords to dazzle and confuse the prospective buyer. This can be particularly obvious when looking at drivelines. The terms four-wheel drive, all-wheel drive, and full-time and part-time are bandied about, but what do they actually mean? Are they all the same, meaning all wheels are driven or is there more to it? Let’s dive into the technology and find out.
Part-time four-wheel drive is the simplest system, most commonly found on older off-road vehicles like Jeeps, Land Cruisers and Land Rovers up to the early 1990s, as well as pickup trucks and other heavy duty applications. In these vehicles, the engine sends its power to a transfer case, which sends an equal amount of torque to the front and rear differentials, and essentially ties their input shafts together. This is good for slippery off-road situations, as some torque is provided to both axles at all times. However, this system has the drawback that it can’t be driven in four-wheel drive mode at all times. With the front and rear differentials rotating together, any difference in rotational speed between the front and rear wheels — such as from turning a corner or uneven tyre wear — would cause a problem. The drive shaft going to one differential would want to turn further than the other, a problem known as wind-up.
Continue reading “The Difference Between 4WD And AWD”
While plenty of automotive enthusiasts are all about carving corners at the local track days, it’s a special breed that leaves tarmac behind for the dusty trail ahead. If your chosen ride is of the four-wheelin’ variety, here’s how you can modify it to dominate the dirt and mud.
Handling The Terrain
Building a good offroad rig requires a very different focus than building a car for street performance. A screaming high-performance engine is of no use when your tires are spinning in the air because you’re stuck in deep sand or on top of a pointy rock. Instead, four wheelers are concerned with a whole different set of parameters. Ground clearance is key to getting over obstacles without getting stuck, and good articulation is key to keeping your wheels on the ground and pushing you forward in deep ruts and on crazy angles. You’ll also want plenty of low-down torque, and tyres that can grip up in all conditions without snagging a puncture. It’s a whole different ballgame, so read on!
Continue reading “How To Get Into Cars: Offroading Mods”
For an electronics person, building the mechanics of a robot — especially a robust robot — can be somewhat daunting. [Jithin] started with an off-the-shelf 4 wheel drive chassis to build an off-road Arduino robot he calls the Badland Brawler. The kit was a bit over $100, but as you can see in the video below, it is pretty substantial, with an enclosed frame and large mud tires.
The remaining parts include an Arduino, a battery, and a motor driver IC. The Arduino is one with WiFi (an MKR 1000, in fact) and there’s a phone app for controlling the robot.
Honestly, once you have the chassis taken care of, the rest is pretty easy. Of course, the phone app is a bit more effort, but you could replace it in a number of ways. Blynk, comes to mind, for example.
The motor drivers are easy to figure out. This would be a great platform for some sensors to allow for more autonomy. We liked how the frame had mount points for a lot of different boards and sensors and could hold everything, for the most part, inside. That’s probably a good idea for a robot which will be traversing rugged terrain.
If you do decide to roll your own app with Blynk, we’ve done it with a very different kind of robot. Four-wheel drive robots don’t have to be big, as we’ve seen in the past.
Continue reading “Badland Brawler Lets Arduino Tackle Terrain”
If you know me at all, you know I’m a car guy. I’m pretty green as far as hardcore wrenching skills go, but I like to tackle problems with my vehicles myself – I like to learn by doing. What follows is the story of how I learned a few hard lessons when my faithful ride died slowly and painfully in my arms over the final months of 2016.
For context, my beast of a machine was a 1992 Daihatsu Feroza. It’s a 4WD with a 1.6 litre fuel injected four-cylinder engine. It had served me faithfully for over a year and was reading around 295,000 kilometers on the odometer. But I was moving house and needed to pull a trailer with all my possessions on an 800 km journey. I didn’t want to put the stress on the car but I didn’t have a whole lot of choice if I wanted to keep my bed and my prized Ricoh photocopier. I did my best to prepare the car, topping up the oil which had gotten perilously low and fitting new tyres. I’d had a hell of a time over the winter aquaplaning all over the place and wasn’t in the mood for a big ugly crash on the highway. Continue reading “Fixing My 4×4: The Battle Of The Bent Valves”
For some people, R/C cars just aren’t enough. [djMedic2008] has gotten his hands on a monstrous 1/5 scale wheel loader. The loader weighs in at 500lbs, and can lift up to 250 lbs. It was built several years ago as a prototype by [Richard] at Tiny Titan Earth Movers.
The design is based upon huge machines made by companies like Caterpillar and Komatsu. The 4WD system is driven a DC motor through a worm gear reduction. Bucket operation and steering are both operated by a hydraulic system driven by an electric pump. Just like the full-scale machines, the mini loader uses an articulated steering system. The front wheels are locked in place while the entire chassis bends at the middle pivot point. This allows for a much stronger solid front axle.
After several years of hard life, the loader came to [djMedic] in need of some TLC. The biggest issue was that the rear axle bevel gear had lost several teeth. This gear is under enormous loads when the loader is turning. A gear made of harder steel was the easy answer. Thankfully, you can order high carbon steel bevel gears from Amazon. The repair video gives us a look at the design of the loader. The main components of the machine are welded up from steel sheet and tube stock. This means that [djMedic] won’t have a hard time finding spare parts for his machine once he puts it to work clearing snow, dirt, or anything else that gets in its way!
Click past the break to see the loader in action!
Continue reading “R/C Wheel Loader Clears Snow, Lifts People”
The picture above looks like a standard four-wheel drive (4WD) touring car. As one looks closer, a few strange things start to pop out. Where’s the motor? 4 electronic speed controls? What’s going on here? [HammerFET] has created this independent drive R/C car (YouTube link) as a research platform for his control system. The car started off life as a standard Schumacher Mi5 1/10th scale Touring Car. [HammerFET] removed the entire drive system. The motor, differentials, belt drive, and ESC all made for quite a pile of discarded hardware.
He replaced the drive system with 4 Turnigy brushless outrunner motors, installed at the chassis center line. To fit everything together, he had to 3D print new drive cups from stainless steel. The Mi5’s CVD drive shafts had to be cut down, and new carbon fiber suspension towers had to be designed and cut.
The real magic lies in [HammerFET’s] custom control board. He’s using an STM32F4 ARM processor and an InvenSense MPU-6050 IMU which drone pilots have come to know and love. Hall effect sensors mounted above each motor keep track of the wheel speed, much like an ABS ring on a full-scale car.
[HammerFET’s] software is created with MATLAB and SimuLink. He uses SimuLink’s embedded coder plugin to export his model to C, which runs directly on his board. Expensive software packages for sure, but they do make testing control algorithms much simpler. [HammerFET’s] code is available on Github.
Since everything is controlled by software, changing the car’s drive system is as simple as tweaking a few values in the code. Front and rear power offset is easily changed. Going from a locked spool to an open differential is as simple as changing a value from 0 to 1. Pushing the differential value past 1 literally overdrives the differential. In a turn, the outer wheel will be driven faster than it would be on a mechanical differential, while the inner wheel is slowed down. Fans of drifting will love this setting!
[HammerFET] is still working on his software, he hopes to implement electronic torque vectoring. Interested? Check out the conversation over on his Reddit thread.
Continue reading “Independent Wheel Drive R/C Car”
[Sparky] notified us of his hack to allow interaction with the core of an Aldi GO Cruise 4300 GPS Windows CE OS. All that’s required is a few programs and registry edits to the GPS, which anyone can accomplish within a few minutes. But we suggest you go slow and double-check your work; nobody wants a bricked system. After you’re done you can run such great programs like the one [Sparky] suggest for 4WD enthusiasts, Ozi Explorer.